I have a thermostatically controlled box that turns on a few circuits around the house at near freezing temperatures. Each curcuit goes to a 110v light bulb that warms various locations, such as well house, hose spigots, etc..
I would like to put an indicator light, led or something, that will come on when the 110v (usually 40 watt) bulb burns out on that circuit.
The radio Shack guys have suggested putting a 2nd bulb in series ... THAT DOESN'T work!
Suggestions, circuit diagrams, will be appreciated!
Relays. Coils operate on 110VAC. One relay wired in series with each light circuit. Any cheap Wall Wart power supply to give you some low voltage DC, you'll use it to power your indicator lights. Use the N C contacts on the relay as the interupt point for your indicator light. Bulb is lit, draws current through relay coil, N C contacts open up, no indicator light. Bulb burns out, no current through relay coil, N C contacts go to normal state, circuit path is completed, lights your indicator.
You're on your own as far as figuring out what to use for indicators, I would use big honkin' LEDs and make sure you use a voltage regulator chip or a dividing network to get the proper supply voltage for them. I'm guessing The Shaq still sells hobbyist stuff like 8 pin DIP DPDT relays with 110 coils?
Putting a small 120v bulb in series as an indicator will work but everything else on the circuit must be in series as well. Just like old Christmas tree lights, if one bulb fails then none of the other bulbs well work. If you have the indicator in series and the other bulbs in parallel then the indicator will remain lit until all of the other bulbs fail.
It should work if you run 240 Volts in a circuit with both lamps of the same wattage. One light at a service panel and the other at the remote location. When all the lights are the service panel were on, you would know all the lights were on.
problem w/ running the bulbs in series, is the additional bulb, and voltage drop, causes both bulbs to run at half strength, hence cooler, defeating the purpose..
You gotta learn your elecrics before you start giving advice like that. You'd need an AC CURRENT relay sized to the lamp bulb current to do what you suggest, and they're not all that easy to come by cheaply
If you put a 110VAC relay coil in series with a 40 watt light bulb, almost all the voltage drop will take place across the relay coil and practically none across the bulb, so the bulb won't light and warm up the OP's frigid stuff.
You might be able to use a low voltage (say 6VAC) relay, with a resistor in parallel with it, sized so there's 6 volts across the relay for a specific wattage bulb.
Gotit?
The rest of what you suggested is OK, but I doubt if Rat Shack ever sold DIP sized relays with 110 VAC coils.
Screw you, ungrateful asshole. You show up here asking for "circuits" like you actually know what you're talking about, and all you really want is for somebody to do all of the work for you. I gave you the basics for 95% of the circuit, and somebody came along and pointed out a flaw in my plan. That's all well and good, so I'm a little rusty, I haven't whipped up a black box from scratch in about 20 years. Do a little reading on relays, coil voltages, etc, and finish the puzzle.
What's that?
Oh that's right, sorry. You don't have a clue, all you really want is for somebody to do all of the work for you.
Hey, M'drurz -- how about coming over and smacking around my wife a little? She's been far too ungrateful lately and needs a good tune-up from someone of your talent.
Between you and the Jesus dude, I'm trying to figure out who's the better entertainment bargain around here.
Awright, so for now, let's forget about relays, wall warts and LED's and get back to basics here.....
Here's something that could work, and it's probably the lowest parts count/cost solution, but no warranties on it or guarantees that it'll satisfy all code requirements. (My advice is worth what you're paying for it. )
A 40 watt bulb will draw about 0.35 amps at 115 volts. If you Google around and look at the specs of various automotive bulbs, you should be able to find a (preferably) 6 volt or a 12 volt bulb rated to draw just a bit more than that current. Get one of those bulbs.
If you put the 40 watt and low voltage bulbs in series across 115 vac the automotive bulb (your "indicator lamp") should light to a little less than full brilliancy, but only drop the voltage to the 40 watt bulb by 5 to 10 volts, so the 40 watt bulb will produce close to it's normal heat output.
A little experimenting should get you there....Unless my approach gets screwed by the turnon surge of the 40 watt bulb blowing out the automotive bulb. If that happens, get back over here and I'll give you a more complex solution guaranteed to work.
Gosh, I hope that someday a doctor doesn't decide to give you the same kind of response if you or a loved one gets rushed to the hospital in dire straits.
I thought these kinds of newsgroups were a place where some of us who know how to do certain things learn how to do other things and in the process occasionally get a chance to "show off how smart we are" without having to do in front of coworkers or close friends.
I'm quite intolerant of stupidity and have been known to suggest autofornication to more than on stupid person on a newsgroup.
But, I have lots of tolerance for ignorance because none of us can possibly be "renaissance men" nowadays and know all there is to know about everything man has learned since he started walking erect.
Jeff (Who finally figured out your pseudonym...It sound like an ad for Depends.)
This is a pretty Rube Goldberg suggestion, but here goes...
If it is normally dark where these bulbs are located, you might be able to use a light sensor to trigger a light back inside your house.
When the thermostat kicks in, it sends power to the heating bulb. It could also send power to a light sensor near the bulb. The output of the light sensor leads to a light bulb conveniently located in your house where you will notice it. If the heating light bulb is on ( i.e. not burned out ), its light will cause the light sensor to keep your interior indicator bulb off. If the heating light bulb is off ( i.e. burned out ), there will be no light, so the light sensor will cause your interior indicator bulb to turn on. Because the light sensor(s) are initially powered by the same power source as the heating light bulb, they will not send power to your interior bulbs unless the thermostat determines that it is cold enough to be sending power out anyway.
Alternatively, you could get one of those wireless weatherstations ( I have a Boston Scientific ) with the outdoor sensors. My weatherstation lets me ( not that I do it ) set an alarm to go off if the temperature ( or rainfall or windspeed ) goes above or below a certain value. If your heating light bulbs go out ( or if there is some malfunction on your circuit - like a power failure ) the alarm will go off and you can fix the problem ( assuming you are home ).
I'll give it a try ... I never asked for guarentees ... only help, which I appreciate!
Robert Ringer once wrote about a giant pinsetter in the sky... go bowling, see those pins flying every which way... well the pinsetter comes down and no matter where they went, they still get set where they are supposed to go..
In other words, jerks eventually get set down just where they are supposed to go..
Fresh from The Department of Flawed Analogies, to your newsreader:
Nice try, but no. I wouldn't walk up to the doctor and say I intended to treat her myself (indicating that I had a basic idea of how to proceed) and then ask him for a roadmap and some clues.
It's called a joke, I doubt if it had much effect on you!
That's a trifle, um, unnecessary. Expending double the power, extra breaker, somewhat code-violationish etc.
The other posting about using 6V lights in series current-matched to the
120V light is a better one. The main trick is getting 6V sockets that don't require you to attach either side to a chassis.
Another idea is to use a much higher wattage 120V bulb as an indicator in series on 120V. Ie: a 40W as the "heater", and 100W as the indicator. The thing will draw something less than 40W, which should be enough to get the 100W to glow somewhat. Pick a clear bulb to see better. Experiment...
Me? I'd probably drill holes in the enclosures, and if I felt like it, glue some clear plastic over the holes. If the heater bulb is working, you'll see the glow - like a pilot light.
A little more elegant would be to pick a series resistor that, when the "heater" bulb was at full power, corresponded to about a 2-3 volt drop. Ie, on a 100W bulb, a 5W 2 or 3 ohm resister. In parallel with the resistor, install a LED and, appropriately sized resistor in series (a few hundred ohms I think). Polarity of LED doesn't matter.
This is probably the most expensive solution. How about one of these:
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A smart power strip. It consists of a sense resistor controling a relay. Plug your heater lamp into the control outlet and your indicator lamp into one of the switched outlets.
I have 3 of them for use on various computer and audio equipment. Bought two from Radio shack (who no longer sells them) and 1 from cyberguys.com (who also no longer sells them) (big help I am).
1) The type of wall switches with a neon lamp which glows when the switch is OFF (handy for finding the switch at night) can also be used to "test" to see if there is a load on the other end.
2) It is downright silly to use a delicate and limited life lamp for an HEATER. Do it right the first time and BUY and install "pump house heaters" which automatically come on when the temperature gets below 40F or so.
The best way of protecting pipes is with the special heat tape that turns itself off as it gets warm.
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